What bullet are you getting that speed with? Does the RS Magnum powder seem to burn pretty clean? I would like to try it in my bigger guns but can't find it for sale anywhere in 200 miles. I will have to pay a haz mat if I end up ordering it. I just want to learn more about it before I order it.

HG, If you can get a couple buddies together and buy powder, give Graf and Sons a try. Grafs.com, we buy powder in bulk usually 45 to 50 pounds. My local dealers cant beat their price and at 32 pounds they knock off the haz mat fee.

Ramshot magnum works very very well in the 257 stw. Mine likes 84 grains and a 100 grain bt good for 3900 fps out of a 30 inch lilja. Another great load is 80 grains of magnum and the 115 barnes triple shock good for 3600 fps. With the big 257 you have to very careful of powder bridging with extruded powder. I tried r25 once with mild loads and blew primers out. I would stick with ball powders and play with your seating depth. And yes ramshot magnum burns very clean. I would use the fed215 primer exclusively as it is the hottest on the market and a healthy dose of any ball powder needs some good ignition. Cheers!

That is really good. I can only get 3700 with that bullet in my 26" barrel using the IMR-7828 in a 257Wby. I love ball powder. I will buy some as soon as I get a chance to. How is your extreme spread for 10 shots? Mine runs 7 fps.

I would say with the barrel length you are using you are getting more velocity then you should be with that bullet.

The Pac Nor will probably be faster then the Liljas I generally use because the Liljas have tighter bores but in your barrel length, I have found a 27" Lilja barreled 257 STW will begin to loosen primer pockets at around 3800-3850 fps.

Many smiths say 4100 fps with a 100 gr bullet is possible in the STW in a 28" barrel. From what I have seen with over a dozen different 257 STWs is that they are being extremely optimistic about velocity potential of the round in this length barrel.

In a Lilja 30" pipe, 3950 fps is about the top comfortable load with a 100 gr bullet. As I said, your Pac Nor will more then likely have a bit looser bore which will allow a bit more velocity but I would have to say you are topped out where you are. In fact I am suprised your getting that much velocity to be honest.

FiftyDriver
My Gunsmith told me he didn't belive we could get these this kind of speed, but we are. If you remember a while back I told you we are using a custom reamer more freebore and more lead. we are probly going to give up a couple .1 MOA for the extra speed, but as long as it shoot under .5 MOA it will work for hunting.
DR B

Yes, a bit of freebore will free things up significantly that is for sure.

I used Retumbo exclusively in my personal 257 STW rifles when I was hunting with that round but that was with 130 gr bullets which I loaded to just shy of 3500 fps.

With about 50% of the rifles I have tested Retumbo in with the 100 gr bullet weights, powder bridging was an issue which is why the need for ball powder. With the heavier pills this was not an issue. Don;t know why to be honest but with the 130s, Retumbo was very well behaved and shot very well. Sub 2" groups at 500 yards was pretty common.

From what I have seen with powders like AA8700 in the STW, I would say US869 will be to slow burning to get top velocities and I would suspect powder fouling will be an issue because you will not be able to get chamber pressures up high enough with a 100 gr bullet to get a good clean burn.

May be wrong but this is what I have seen in the STW with powders such as AA8700 and H-870.

With heavy bullets these powders work very well. Starting ar 120 gr and up to 156 gr, they may be the very best powder choices out there for the real big 257 magnums.

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